This study is validating the use of breath test compared to scintigraphy for measurement of gastric emptying and preliminary results indicate that analytical methods published in the literature are inadequate. We are therefore applying novel mathematical models to breath test data to more accurately "predict" scintigraphic gastric emptying data. We have completed this protocol. We performed simultaneous 13C-octanoic acid breath test and scintigrahy in 23 patients with diabetes and 6 healthy volunteers. Preliminary data of this work was presented at the American Gastroenterological Association Annual Meeting in May 1998. We are now developing a new, accurate model for solid gastric empthing using a multiple linear regression analysis with the same method previously used in the 13C-spirulina breath test; a full manuscript of this work will be submitted for publication.